Biologist Lincoln Brower of Virginia's Sweet Briar University
has been studying monarch butterflies and their astonishing annual
migration to the central Mexican highlands for 45 years. He helped us
square away the facts in Melina Bellow's feature on the monarchs, "In Search of Magic,"
in our November/December issue. We caught up with him to find out more
about his work and gather some suggestions for traveling to Mexico to
witness the magic yourself.
Why do the monarchs make this journey?
Monarchs are similar in their migratory behavior to many songbirds that invade our temperate zone in the summer, but cannot survive during the winter and so they migrate back into their tropical habitats in the fall. In the U.S. and Canada, milkweeds and nectar sources become superabundant in the spring and summer but completely freeze back in the winter. The big difference between birds and monarchs is that the monarchs return to Mexico, to the same trees in successive winters although they themselves have never been there before. They are the grandchildren and great-grandchildren of the monarchs that were there the previous year. The entire migration is an inherited behavior pattern and we are just beginning to understand this incredible behavior.
What are some of the most interesting aspects of the migration you've discovered?
We have shown how critical the intact oyamel fir canopy is in providing a very tight microclimate that allows the monarchs to avoid freezing during winter storms. The fir trees serves both as a blanket and umbrella for the monarchs.
Monarchs are similar in their migratory behavior to many songbirds that invade our temperate zone in the summer, but cannot survive during the winter and so they migrate back into their tropical habitats in the fall. In the U.S. and Canada, milkweeds and nectar sources become superabundant in the spring and summer but completely freeze back in the winter. The big difference between birds and monarchs is that the monarchs return to Mexico, to the same trees in successive winters although they themselves have never been there before. They are the grandchildren and great-grandchildren of the monarchs that were there the previous year. The entire migration is an inherited behavior pattern and we are just beginning to understand this incredible behavior.
What are some of the most interesting aspects of the migration you've discovered?
We have shown how critical the intact oyamel fir canopy is in providing a very tight microclimate that allows the monarchs to avoid freezing during winter storms. The fir trees serves both as a blanket and umbrella for the monarchs.
Continue reading Following Monarchs to Mexico.











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